A computer model was developed to analyze the costs to Medicare and the potential procedure volume associated with alternative strategies for treatment of acute myocardial infarction. The expected cost per case to Medicare for initial hospitalization was approximately $7,200 for conventional treatment, $7,900 for treatment with intravenous streptokinase and $8,400 for treatment with recombinant tissue-type plasminogen activator (rt-PA). The expected cost per case for use of streptokinase or rt-PA in combination with cardiac catheterization performed either emergently or at 48 h was in excess of $11,000. These cost estimates do not reflect the cost of thrombolytic drugs themselves because Medicare has not adjusted its hospital payment rates to take account of such costs. Although both streptokinase and rt-PA will increase costs to Medicare for hospitalizations for acute myocardial infarction, both agents will do so at a reasonably low cost per additional life saved--between $50,000 and $60,000. Emergency and 48 h catheterization strategies are considerably less cost-effective. Regarding procedures, this model suggests that for every 1,000 patients treatment with streptokinase will result in an additional 76 coronary angioplasty procedures and 26 coronary artery bypass operations, whereas treatment with rt-PA will result in an additional 122 angioplasty procedures and 43 bypass operations compared with conventional treatment. Thrombolytic treatment is thus likely to increase substantially the volume of cardiac catheterization, coronary angioplasty and coronary artery bypass surgery performed in the United States.